Door latching mechanism



G. E. RHODES ETAL 3,076,328 DOOR LATCHING MECHANISM Feb. 5, 1963 Filed June 24, 1960 5 Sheets-Sheet l g m m Y o e E T00 N N K R E w .n 0 ha W EMB n f n E G WITNESSES Feb 1963 a. E. RHODES ETAL 3,076,323

noon uu'cumc MECHANISM Filed June 24, 1960 3 Sheets-Sheet 2 Fig.2.

Fig.3.

Feb. 5, 1963 3 Sheets-Sheet 3 Filed June 24, 1960 Fig.5.

United States atent "ice 3,676,328 DOOR LATCHING MECHANISM Glenn E. Rhodes, Monroevilie, and Charles W. Koenig, Forest Hills, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed June 24, 1960, Ser. No. 38,599 7 Claims. (Cl. 70-92) This invention relates to door latching mechanisms in general, and to emergency latch releasing mechanisms in particular.

It is customary to house certain indoor switch-gear mechanisms in weather-proof housings having an enclosed aisle space or work area adjacent the switchgear units to provide a sheltered area for maintenance personnel in inclement weather. Doors are usually located at both ends of the aisle. Each door includes a door latching mechanism mounted on the inside of the door, which latching mechanism is operable externally of the door and adapted to be padlocked on the outside to prevent access by unauthorized persons.

Normally, maintenance personnel make entry by unlocking and opening only one of the two doors. Since an emergency situation arising within the housing, such as an explosion or fire, requires fast exit, each door is provided with an emergency latch release mechanism mounted internally of the door and operable to unlatch the door latching mechanism even though the door is padlocked on the outside. This structure is provided so that a person in the aisle may exit quickly through the door other than the one through which entry was made to the housing.

It is an object of this invention to provide a manually operable mechanism effecting quick release of a locked door latch.

It is another object of this invention to provide a door latch release mechanism operable to effect quick release of a locked latch mechanism in response to a single unidirectional manual pushing force.

More specifically, it is an object of this invention to provide in an emergency latch release mechanism a trip bar responsive to a unidirectional manual pushing force to trip a latch operating mechanism normally biased to open the latch.

Other objects will in part be obvious, and will in part appear hereinafter.

In accordance with this invention, latch means mounted on the inside of a door are adapted for latching and unlatching movement with respect to the enclosure by longitudinal motions of operating rod means connected to one end of a latch lever arm mounted for rotational movement about a central shaft extending through the door and rotatable with respect to the door. A handle is fixed to the outside end of the shaft. A retainer plate is fixed to the inside end of the shaft and includes gripping means normally engaging the latch lever arm means under the urging of spring means between the door and the latch lever so that the latch lever is normally gripped by the retainer plate so as to rotate with the shaft to effect latching and unlatching of the latch means. A push bar is provided on the inside of the door and has one end pivoted to the door and the other end pivotally attached to the lever arm to override the spring means and thus effect disengagement between the retainer means and the latch lever means. A torsional spring means stressed between the latch lever and the retainer effects rotation of the latch lever as soon as the latch lever is disengaged from the gripping action of the retainer means, thus forcefully lowering the push bar at the end attached to the lever arm and effecting rotation of the latch lever to in turn effect release of the latch means automatically in 3,076,328 Patented Feb. 5, 1963 response to a push operation of the push bar. The release mechanism is automatically reset by raising the push bar to the original position, thus recharging the torsional spring means and allowing the biasing spring means between the door and the latch lever to effect engagement between the gripping means of the retainer member and the latch lever means.

For a more complete understanding of the nature and scope of this invention, reference may be made to the following detailed description, which may be read in connection with the accompanying drawings, in which:

FIGURE 1 is a fragmentary elevational view of a door showing the latch control mechanism mounted on the inside of the door;

FIGURE 2 is an enlarged sectional view of portions of the latch release mechanism, taken along the line II-II of FIGURE 1;

FIGURE 3 is an enlarged fragmentary view of the latch release mechanism shown in FIGURE 1;

FIGURE 4 is a sectional view taken along the lines IVIV of FIGURE 1; and,

FIGURE 5 is an enlarged sectional view taken along the line VV of FIGURE 1.

Referring to FIGURE 1, there is shown the general arrangement of a door 5 as seen from the inside and upon which is mounted a latch mechanism 6, and those portions of a latch operating mechanism 7 which are mounted on the inside of the door 5.

The latch mechanism 6, as best seen in FIGURE 5, comprises a finger member 8 pivotally mounted at pin 9 on a bracket 10 suitably attached to the upper inside portion of door 5. In the latched position shown, the latch finger -8 engages the inner periphery of flange 11 comprising the opening in the enclosure to which the door 5 is attached. In this latched position, the latch 6 urges the inner surface of the door 5 against the flange 11 to effectively seal the enclosure when the door is closed. The latch finger 8 is adapted for clockwise motion about pivot point 9 under the urging of a latch operating rod 12 connected to the latch finger 8 by means of a clevis 13. Specifically, the upper end of the clevis is attached to the finger latch 8 by means of a lost motion slot 14 on the clevis engaging a pin 15 on the latch finger 8 at a point spaced from the pin 9. The lower end of the clevis is adjustably attached to the threaded upper end of the operating rod 12. Thus the length of the rod may be adjusted by turning the clevis on the rod. A lock nut 17 is provided for securing the clevis in its adjusted position. It is seen that longitudinal movement of the rod 12 upwardly effects a latching operation of the door while a downward movement of the operation rod efiects a corresponding unlatching operation of the door and latch means 6.

It is to be understood that the lower end of the door (not shown) may be provided with an identical latch means 6 and operating rod 12. The upper operating rod 12 and a portion of the lower operating rod 12 are both shown in FIGURE 1.

The latch operating mechanism 7 for eflfecting latching and unlatching operation of the latch fingers 8, 8 mounted on the inside of the door is shown in detail in FIGURES 2 and 3. Specifically, a latch lever 18 is provided for elfecting movement of the operating rods 12, 12, as hereinbefore described, and comprises an upper lever arm 19 attached to the lower end of the upper operating rod 12 by means of a pivot pin 20, and a lower lever arm 21 pivotally attached to the upper end of lower operating rod 12 by means of a pivot pin 22. The latch lever 18 is adapted for rotation about a point midway between the pivot pins 20, 22 in a manner hereinafter described to effect latching and unlatching movement of the latch operating rods 12, 12.

An emergency lever arm 23 extends laterally from the distal end of upper lever "arm 19 for effecting emergency operation of the latch lever 18 as will be hereinafter described in detail. A fulcruin arm 24 extends laterally from the distal end of lower 'lever arm 21 in a direction opposite that of the emergency lever arm 23 and cooperates with the emergency arm 23in a manner-hereinafter described to effect emergencyoperation of the latch lever 18. V

In order to provide for rotation of the latch lever 18 from the position shown in FIGURE '1 to effect an unlatching operation of the latch means 6, 6there is provided a bushing 3 fixedly attached to the inside of the door 5, as by welding, and including a restricted neck portion 4 extending through the doors. A shaft 25 extends through the bushing and comprises an integral bearing portion 26 on one end having a circular cross-section for slidably engaging the inner periphery of the bushing 3, the remainder of the shaft having a rectangular cross section slightly restricted with respect to the bearing portion 26 and being threaded throughout its length. A handle 27 is fixed externally of the door to the bearing end portion 26 of the shaft 25 to provide the manually responsive means for rotating shaft 25 about its longitudinal axis. A bearing 28 is threadedly sleeved on the shaft 25 in abutting relationship with the bearing portion 26.

The latch lever 18 is sleeved on the bearing '23 by means of a circular aperture 29 having a circumference slightly larger than the circumference of the bearing 28 to provide for transverse movement of the latch lever 18 along the bearing 28 and to further provide for wobble movement between the'bearing 28 and the latch lever as hereinafter described. A nut 30 is threaded on the shaft 25 in abutting relationship with bearing 28 to fix the bearing 28 on the shaft and to serve as a stop for transverse movement of the latch lever means 18. A compression spring 31 encircles the shaft 25 and bushing 3 and is compressed between the latch lever 18 and the inside of the door to normally urge the latch lever 18 in abutting relationship with the nut 36 as shown in FIG. 2. A lock washer 32 is sleeved on the shaft in abutting relationship with the nut and serves as a seat for the main body portion of a retainer 33 sleeved onto the rectangular portion of shaft 25 by means of a mating rectangularaperture 35 in the retainer 33.

The retainer is basically U-shaped, as best seen in FIGURE 2, and includes a pair of legs 36 and 37 on opposite ends of the apertured body portion 33, with the legs extending transversely of shaft 25 from the body 33 to a point where the ends of legs 36 and '37 straddle the latch lever means 18. Leg 37 is slightly longer than leg 36 to provide for release of the latch lever means in a manner to be hereinafter described in detail. The re tainer 33 is fixed to the shaft 25 by means of a lock washer 38 and a nut 39.

From the foregoing description it is seen that when shaft 25 is rotated counterclockwise in FIGURE 3, the retainer 33 necessarily rotates with the shaft 25, because of the rectangular form of the shaft 25 and aperture 35, causing legs 36 and 37 to bear laterally against'thelatch lever 18 to effect rotation of the latch lever with the shaft 25. It is seen that counterclockwise rotation of latch lever 18 from the position shown in FIGURE 1 pulls the operating rods '12, 12 longitudinally toward the shaft 25, thus effecting unlatching action of the previously described latch means 6, 6. Conversely, clockwise rotation of the latch lever means from the unlatched position to the position shown in FIGURE 1 effects latching of the latches 6, 6.

Lock means, such as a padlock 34, may be provided through aperture 40 in the handle 27 and a suitable mating apertured stud 41 fixed to the outside of the door 5 to prevent rotation of theshaft 25, thus preventing unlatching operation of the latch means ,6, 6. The locking aperture and stud may be placed on eithe'r'side of the 4 shaft 25 as desired. -However,-inasmueh as the handle is preferably of the off-center type with respect to shaft 25, the door stud 41 would be positioned inside the handle if moved to the other side to permit rotation of the handle when the lock is removed.

In order to provide for emergency release of the latch means 6, 6 from inside the door even if the normal latch operating means is locked on the outside, there is provided a push bar 42 pivoted at one end 43 to the inside of the door (FIG. 4), and pivotally attached at the other end 44 to the end of the previously mentioned emergency release lever 23 on the latch lever arm 19. For cooperation with the push bar 42, there is provided a fulcrum bar 45 mounted vertically at its ends on the inside of the door 5 adjacent the shaft 25 so as to continuously overlap the previously mentioned fulcrum lever arm 24 on the latch lever 18, as best seen in FIGURES 3 and 4.

In operation of the emergency release mechanism, the push bar 42 is pushed inwardly from the normal position shown iii-FIGURE 4 toward the door, thus effecting inward motion of the latch lever longitudinally of the bearing 28 about the fulcrum bar 45 as seen from the top in FIGURE 4 and against the bias of biasing spring 31. This inward motion of the latch lever 18 against the force of spring 31 causes compression of spring 31 permitting the latch lever 18 to move clear of the legs 36, 37 of the retainer 33. The previously described uneven lengths of the legs 36 and 37 provide for simultaneous release of both legs from the latch lever 18 as the latch lever 18 moves about the fulcrum bar 45. The latch lever is thus released from the grip of the retainer 33 and made free to pivot counterclockwise around the locked shaft 25 to effect an unlatching operation of latches 6, 6.

In order to provide for automatic rotation of the latch lever 18 after it clears the legs 36 and 37 of the retainer 33, as described above, there is provided a torsion spring 46 encircling the shaft 25 between the latch lever 18 and the retainer body 33. One end of the torsion spring 46 is hooked over the bottom edge of the retainer 33 in a suitable groove while the other end is hooked in a suitable groove to the upper arm 19 of the latch lever so that when the latch lever is held between the legs 36, 37 of the retainer means 33, the torsion spring 46 is under stress tending to rotate the latch lever counterclockwise with respect to the retainer 33. However, inasmuch as the torsion force of spring 46 is between the latch lever 18 and the retainer plate 33 the torsion effect of the spring 46 is completely independent of the shaft 25 under normal operating conditions inasmuch as the legs 36, 37 counteract the torsion effect of spring 46.

When the push bar 42 is operated to effect movement of the latch lever longitudinally of the bearing 28, as previously described, the stored energy in the torsion spring 46 releases to effect rapid counterclockwise rotary movement of the latch lever 18 around the bearing 28 and the shaft 25 as soon as the latch lever 18 clears the legs 36, 37. The counterclockwise rotation of the latch lever 18 effects unlatching of the latches 6, 6 and at the same time forcefully lowers the push bar 42 to the broken line position shown in FIGURE 1. Thus, an inward push on the push bar 42 effects rapid release of the door latching, mechanism 6, 6.

Resetting of the emergency latch release mechanism is accomplished by merely raising the push bar 42 from the dot-dash line position to the original position, thus storing energy in the torsion spring 46. When the latch lever 18 returns to the original raised position, the coil spring 31 urges the latch lever between the legs 36, 37 of the retainer 33, thus nullifying the torsional effect of the torsion spring 46 and conditioning the latch lever to be operated under the control of the shaft 25 and the fixed retainer 33 in the manner previously described.

Since "certain changes may be made in the above dein the above description and shown in the accompanying drawings should be considered as illustrative and not in a limiting sense.

We claim as our invention:

1. Latch control apparatus adapted for use with a latch means, comprising: latch lever means movable to operate the latch means; means for connecting the latch means to the latch lever means; first operating means releasably engaged with the latch lever means for operating the latch lever means; lock means for preventing operation of the first operating means; means biasing the latch lever means into engagement with the first operating means; second lever operating means adapted to automatically operate the latch lever means when the latch lever means is disengaged from the first operating means; and, means including a push bar connected to the latch lever means and operable to effect disengagement between the latch lever means and the first operating means.

2. Latch control apparatus, comprising: a shaft adapted to be mounted for rotational movement about the shaft axis; a latch lever sleeved on the shaft and adapted for independent movement with respect to the shaft; latch lever retainer means fixed on said shaft and including means engageable with the latch lever for preventing movement of the latch lever from a first position with respect to the latch lever retainer means; spring means connected between the latch lever and the latch lever retainer means for biasing the latch lever around the shaft from said first position to a second position with respect to the latch lever retainer means when the latch lever is disengaged from the latch lever retainer means; resilient means urging the latch lever into engagement with the latch lever retainer means; and, means including a push bar connected to the lever means for moving the lever means out of engagement with the latch lever retainer means.

3. Latch control apparatus, comprising: a lockable shaft adapted to be mounted for rotational movement about the shaft axis; a latch lever sleeved on the shaft and adapted for independent rotational and transversal movement with respect to the shaft; latch means operable in response to rotational movement of the latch lever; latch lever retainer means fixed on the shaft and including means engageable with the latch lever for preventing movement of the latch lever from a position with respect to the latch lever retainer means as the shaft is rotated; torsion spring means connected between the latch lever and the latch retainer to bias the latch lever around the shaft from said first position to a second position with respect to the latch lever retainer means; compression spring means normally urging the latch lever transversely of the shaft into engagement with the movement preventing means; means including a push bar for urging the latch lever transversely of the shaft against the compression spring means to effect disengagement between the movement preventing means and the latch lever.

4. Latch apparatus, comprising: a lockable shaft adapted to be mounted for rotational movement about its axis; a latch leverloosely sleeved on the shaft by means of an aperture larger than the shaft and adapted for independent movement with respect to the shaft; said lever means having end portion means and two side portion means; latch lever retainer means fixed on the shaft and including leg portions extending longitudinally of the shaft for straddling engagement with the latch lever means at the said side portions for preventing movement of the latch lever from a first angular position with respect to the latch lever retainer means as the shaft is rotated; torsion spring means connected between the latch lever and the latch retainer for biasing the latch lever around the shaft from said first angular position to a second angular position with respect to the latch lever retainer means; compression spring means normally urging the latch lever transversely of the shaft into engagement with said leg portions; a fulcrum bar fixed with respect to the shaft mounted at a point spaced from the shaft and engaging one of said two sides of the latch lever in opposition to the compression spring means; and, push bar means having one end pivotally attached to the other of said two side portions and having the other end mounted for pivotal movement at a point fixed with respect to the shaft mounting and spaced from said shaft whereby the application of the manual force to the push bar transversely of said shaft effects transverse movement of the lever along said shaft to effect disengagement between the leg portions of said latch lever retainer means and the latch lever means.

5. In combination: a door; latch means mounted on the inside of the door for latching the door to an enclosure; a shaft extending through the door and mounted in the door for rotation about its axis; a latch operating lever means sleeved in said shaft on the inside of the door connected to the latch means and adapted for independent rotational and longitudinal movement on said shaft; retainer means fixed on said shaft and including gripping means engageable with the lever to prevent relative motion between the shaft and lever when the shaft is rotated; spring means compressed between the inside of the door and the lever for biasing the lever longitudially of the shaft into engagement with the gripping means; torsion spring means stressed between the retainer means and the lever when the lever is engaged with the gripping means for biasing the lever rotationally about the shaft; means on the outside of the door for locking the shaft; means mounted on the inside of the door including a push bar connected to the lever and movable perpendicularly with respect to the door against the bias of said compression spring to move the lever longitudinally of the shaft for effecting disengagement between the lever and the gripping means.

6. An operating mechanism for emergency door latches, comprising: a door; a shaft extending through the door and rotatable about its axis; latch means on the inside of said door; latch lever means on the inside of said door and operable to operate said latch means; means on said shaft on the inside of said door normally engaging said latch lever means for operation by rotation of said shaft, said latch lever means being operable to be disengaged from said last mentioned means; means on the inside of the door including stored energy means operable when said latch lever means is disengaged to automatically operate said latch lever means in a latch operating mode; means on the inside of the door including a push bar connected to the lever means to disengage said engaging means from the latch lever means; and, means operable from the outside of the door to lock said shaft.

7. Latch control apparatus, comprising: a door; a shaft extending through said door and adapted for rotation about its axis; a latch lever sleeved on the shaft on the inside of said door and adapted for independent movement with respect to the shaft; latch lever retainer means fixed on said shaft and including means engageable with the latch lever for moving the latch lever with the shaft; latch means on the inside of the door operable in response to movement of the latch lever; spring means for biasing the latch lever around the shaft when the latch lever is disengaged from the latch lever retainer means; resilient means biasing the latch lever into engagement with the latch lever retainer means; and means including a push bar for disengaging the latch lever from the latch lever retainer means.

References Cited in the file of this patent UNITED STATES PATENTS 911,177 Stevenson Feb. 2, 1909 941,000 Willison et al Nov. 23, 1909 1,056,937 Pratt Mar. 25, 1913 1,488,611 Phillips Apr. 1, 1924 

1. LATCH CONTROL APPARATUS ADAPTED FOR USE WITH A LATCH MEANS, COMPRISING: LATCH LEVER MEANS MOVABLE TO OPERATE THE LATCH MEANS; MEANS FOR CONNECTING THE LATCH MEANS TO THE LATCH LEVER MEANS; FIRST OPERATING MEANS RELEASABLY ENGAGED WITH THE LATCH LEVER MEANS FOR OPERATING THE LATCH LEVER MEANS; LOCK MEANS FOR PREVENTING OPERATION OF THE FIRST OPERATING MEANS; MEANS BIASING THE LATCH LEVER MEANS INTO ENGAGEMENT WITH THE FIRST OPERATING MEANS; SECOND LEVER OPERATING MEANS ADAPTED TO AUTOMATICALLY OPERATE THE LATCH LEVER MEANS WHEN THE LATCH LEVER MEANS IS DISENGAGED FROM THE FIRST OPERATING MEANS; AND, MEANS INCLUDING A PUSH BAR CONNECTED TO THE LATCH LEVER MEANS AND OPERABLE TO EFFECT DISENGAGEMENT BETWEEN THE LATCH LEVER MEANS AND THE FIRST OPERATING MEANS. 